Plants and Animals
Leptodea leptodon Scaleshell
Key Characteristics
The scaleshell is a medium sized (1 to 4 inches) mussel with an elongated, compressed, thin, translucent shell with a rounded anterior margin. The beak is low and positioned in the anterior quarter of the shell length and has 4 to 5 very fine double-looped ridges. The cardinal teeth are rudimentary, single, and compressed. The nacre is bluish to purple, occasionally with copper or salmon overcast, and highly iridescent.
Status and Rank
US Status: LE - Listed Endangered
State Status: X - Presumed extirpated (legally 'threatened' if rediscovered)
Global Rank: G1G2 - Rank is uncertain, ranging from critically imperiled to imperiled
State Rank: SX - Presumed extirpated
Occurrences
| County | Number of Occurrences | Year Last Observed |
|---|---|---|
| Barry | 1 | 1939 |
| Lenawee | 2 | 1939 |
| Monroe | 2 | Historical |
Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.
Habitat
The scaleshell occurs in riffle areas of clean, clear medium to large rivers. They are associated with strong currents and substrates of mud and sand, or mixtures of gravel, cobble, and boulder.
Natural Community Types
For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.
Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.
Management Recommendations
The species is severely impacted by alteration and inundation of channels, siltation from agriculture and clear-cutting, chemical and organic pollution. Habitat loss caused by degradation from construction activities and intensive land use also threatens the scaleshell mussel. Also impacted by exotic zebra mussels. Maintenance or establishment of vegetated riparian buffers can help protect mussel habitats from many of their threats. Control of zebra mussels is critical to preserving native mussels. And as with all mussels, protection of their hosts habitat is also crucial.
Active Period
Breeding from first week of May to fourth week of June
Survey Methods
Litter sampling
Survey Period: From first week of April to first week of October
Time of Day: Daytime
References
Survey References
- Nekola, J.C. 2003. Large-scale terrestrial gastropod community composition patterns in the Great Lakes region of North America. Diversity and Distributions 9:55-71.
Technical References
- Applegarth, J.S. 1999. Management recommendations for terrestrial mollusk species, Megophix hemphilli, the Oregon Megomphix. Version 2.0. 39pp.
- Baker, F.C. 1939. Fieldbook of Illinois Land Snails. Illinois Natural History Survey Manual 2, Urbana, Illinois. 166pp.
- Berger, B. and R. Dallinger. 1993. Terrestrial snails as quantitative indicators of environmental metal pollution. Environmental Monitoring and Assessment 25(1):65-84.
- Kay, E.A. 1995. Hug a slug, save a snail: A status report on molluscan diversity and a framework for conservation action. Pp. 53-79. In: E.A. Kay (ed). 1995. The Conservation Biology of Molluscs. IUCN, Gland, Switzerland.
- Nekola, J.C. 2002. Effects of fire management on the richness and abundance of central North American grassland land snail faunas. Animal Biodiversity and Conservation 25(2):53-66.
- Nekola, J.C. 2003. Large-scale terrestrial gastropod community composition patterns in the Great Lakes region of North America. Diversity and Distributions 9:55-71.
- Notten, M.J.M., A.J.P. Oosthoek, J. Rozema, and R. Aerts. 2006. Heavy metal pollution affects consumption and reproduction of the landsnail Cepaea nemoralis fed on naturally polluted Urtica dioica leaves. Ecotoxicology 15(3):295-304.
- Regoli, F., S. Gorbi, D. Fattorini, S. Tedesco, A. Notti, N. Machella, R. Bocchetti, M. Benedetti, and F. Piva. 2006. Use of the Land Snail Helix aspersa as Sentinel Organism for Monitoring Ecotoxicologic Effects of Urban Pollution: An Integrated Approach. Environmental Health Perspectives 114(1):63-69.